1. Field of Invention
This invention relates to polybenzimidazolone polymers and a process for their production. More particularly this invention relates to polybenzimidazolone polymers produced by a process using hexafluoro aromatic tetraamines.
2. Prior Art
Polybenzimidazoles are a group of nonflammable polymers which may be formed into fibers, films and membranes having outstanding thermal, physical and chemical stability. Processes for their production are disclosed, for example, in U.S. Re. 26,065 and U.S. Pat. Nos. 3,313,783, 3,509,108, 3,555,389, 3,433,772, 3,408,336, 3,549,603, 3,708,439, 4,154,919 and 4,312,976. (All patents mentioned herein are incorporated by reference).
Conventional polybenzimidazoles have been produced by the reaction of at least one aromatic tetraamine with a dicarboxylic acid, an ester of a dicarboxylic acid or a dicarboxylic acid halide. For example, in U.S. Pat. No. 2,895,948, polybenzimidazoles are prepared by the following condensation reaction: ##STR1## wherein R is a group of the class consisting of diphenyl bonds and divalent hydrocarbon radicals and n is from 4 to 8. For other conventional process for the production of polybenzimidazole polymers, see for example U.S. Pat. No. 4,814,530, 4,431,796 and 4,414,383.
While polybenzimidazole polymers produced by the methods disclosed above have been quite useful, they possess certain deficiencies in their processability, solubility, resistance to moisture absorption, tractability and flammability. One method of improving these characteristics has been the replacement of the imidazole hydrogen with less reactive substituents to produce N-substituted polybenzimidazole polymers. See for example U.S. Pat. No. 4,579,915, and 4,377,546.
Another method of improving the polybenzimidazole polymers is to prepare substituted polybenzimidazole polymers. For example, a vast array of substituted tetraamino heterocyclic compounds useful in the preparation of substituted polybenzimidazole polymers are disclosed in U.S. Pat. No. 3,943,125. Although many types of substituted tetraamino compounds are disclosed in the '125 patent, the use of a hexafluoro-substituted reactant to produce substituted polybenzimidazolone compound is not disclosed.
Another method of improving the performance of polybenzimidazole polymers is to modify their structure, such as by producing polybenzimidazolone polymers. The original process for the production of polybenzimidazolone polymers was disclosed in Marvel, C.S., Journal of Polymer Science, Part A, (3), p. 3549 (1965). That article discloses the reaction of a biphenyl tetraamine with a biphenyl dianhydride to produce a polybenzimidazolone polymer.
U.S. Pat. No. 4,260,652 discloses a process for producing a permselective composite membrane wherein a significant number of polybenzimidazolone polymers are disclosed. See for example, column 33 through 44. The polybenzimidazolones disclosed may or may not have bridging members selected from the group consisting of ##STR2## Although, there are a significant number of polybenzimidazolone polymers disclosed, none contain the hexafluoro substituent present in the instant application, nor does the patent disclose the instant process.
U.S. Pat. No. 4,537,974 discloses a diethynylated phenylbenzimidazole compound having the formula: ##STR3## wherein Y is phenyl, cyclohexyl, adamantyl or phenoxylatedphenyl of the formula C.sub.6 H.sub.5 (OC.sub.6 H.sub.4)n (n=1 to 3) and where R.sub.1, R.sub.2 and R.sub.3 are ethynyl, phenoxyethynyl, phenylethynyl, or hydrogen and further wherein at least one of said R.sub.1, R.sub.2 or R.sub.3 is not hydrogen. This product is produced by the reaction of a hexafluoro substituted diaryl material with an aryl ethynyl material. While this reaction uses a hexafluoro material as a reactant, the hexafluoro material is significantly different from that used in the instant invention. In addition, the aryl ethynyl reactant is significantly different from the second reactant used in the instant process for the production of a substituted polybenzimidazolone polymers and the final product produced is also significantly different. See related U.S. Pat. No. 4,587,315.
A significant number of naphthoylene-based benzimidazoles which may or may not contain a hexafluoro substituent are disclosed in a number of chemical abstract articles. See, Chemical Abstracts, Vol. 96, 20, 96:862357c (1982): Chemical Abstracts, Synthetic High Polymers, Vol. 96, 5, 96:20530h (1982); Chemical Abstracts, Synthetic High Polymers, Vol. 92, 9 92:77055d (1980); Chemical Abstracts, Heterocycles, Vol. 92, 609, 92:6465b (1980); Chemical Abstracts, Plastics Manuf. Vol. 90, 29, 90:169374u (1979); and Chemical Abstracts, Plastic Manuf., Vol. 88, 31, 88:90478f (1978). While each of these articles disclose naphthoylene-based benzimidazoles wherein a possible substituent is a hexafluoro substituent, they fail to disclose the process of the instant invention, the types of hexafluoro compounds used in the instant process or the production of polybenzimidazolones.
U.S. Pat. No. 4,713,438 discloses a process for the production of certain polyimides containing CF.sub.3 radicals within their structure. However, it fails to disclose the polybenzimidazolone polymers of the instant invention or suggest the use of 6F monomers for the preparation of polybenzimidazolone polymers.
Accordingly it is an object of the present invention to prepare novel hexafluoro polybenzimidazolone polymers.
It is a further object of this invention to prepare novel polybenzimidazolone polymers using hexafluoro tetraamines as a reactant.
It is a further object of this invention to prepare novel polybenzimidazolone polymers using hexafluoro tetraamines as a reactant that exhibit increased solubility over conventional polybenzimidazole polymers.
It is a still further object of this invention to prepare novel polybenzimidazolone polymers using hexafluoro tetraamines as a reactant which exhibit increased low temperature processibility over conventional polybenzimidazole polymers.
It is a still further object of this invention to prepare novel polybenzimidazolone polymers using hexafluoro tetraamines as a reactant which exhibit low moisture absorption, low flammability and long term thermal stability.
It is a still further object of this invention to prepare novel polybenzimidazolone polymers using hexafluoro tetraamines as a reactant which exhibit increased solvent resistance.
It is an additional object of this invention to prepare novel polybenzimidazolone polymers using hexafluoro tetraamines as a reactant which can be easily blended with other polymers to form useful composites.
These and other objects, as well as the scope, nature and utilization-of the process will be apparent to those skilled in the art from the following description and appended claims.